Metal production and casting



March 4, .195,8

T. T. MAGEI. 2,825,105 METAL PRODUCTION ANUcAsTING Y Filed March 24, 1945 METAL PRUDUCTIN AND CASTING Theodore T. Magel, Cambridge, Mass., assigner to the United States of America as represented by the United States Atomic Energy Commission Application March 24, 1945, Serial No. 584,684

3 Claims. (Cl. 22--65) My invention relates to the production and casting of metal and is more particularly directed to the reduction of metal salts and the concurrent casting thereof.

ln the production of certain metals it frequently is difficult to secure a substantial recovery due to entrapment in the reaction mixture from which it has been produced. This is particularly true where small quantities of metal are prepared since, in such a case, the percent of metal entrapment may become quite large.

ln the reduction of very small quantities it may be found that none of the metal has separated from the slag or the reaction mixture.

Another difliculty in producing very small quantities of a highly corrosive metal is that a high percentage may be lost by reaction with air before a solid billet is obtained.

It is an object of my invention to provide an apparatus for the production of very small quantities of metal.

Another object of my invention is to provide an apparatus for producing very small quantities of a metal and concurrently casting the metal into a billet.

These and other objects of my invention, and the various features and details of the construction and arrangement thereof, are hereinafter set forth with reference to the accompanying drawings, in which:

Figure 1 is a diagrammatic sectional view of an induction furnace embodying various features of my invention; and

Figure 2 is a partial sectional view taken on line 2 2 of Figure l.

In accordance with the present invention it has been found that metallic compounds may be effectively reduced and a high recovery of metal secured by reducing a metal compound at a temperature sufficiently high to form molten metal while subjecting the reaction mixture to a centrifugal force whereby the molten metal is thrown outwardly and is collected. If desired, the body of metal collected may be solidified and a centrifugal casting secured from a metal compound in a single operation. The process is particularly valuable for production of rare metals in small quantities.

The apparatus herein described is particularly adapted to the production of small quantities of uranium from certain salts thereof, for example, uranium tetraliuoride. It is adapted, however, to producing billets of very small quantities of various metals, particularly those having atomic numbers greater than eighty-seven.

Referring to the drawing, Figure l illustrates a suitable apparatus for heating a charge of metal salt forming the metal and concurrently casting the metal into billets or other form.

A horizontal slab it? of heat insulating material is supported in any suitable fashion and may be the Transito top of a laboratory table. A cylinder il also of heatinsulating material is supported vertically by the slab and is located thereon by several angle pieces l2 suitably secured to the slab 10. The cylinder 11 may also be of fa i.

T ransite or of fused quartz, which will stand considerably higher temperatures.

The cylinder 11 serves as a support for an induction coil 15 comprising a plurality of turns of copper tubing suitably spaced thereon and secured thereto.- High-frequency alternating current is supplied to the water cooled coil i5 by means of clamps i7 and i8 and electrical connections and 20, respectively. The circulating-water connections ..3 and 24 may be formed of flexible rubber hose.

A rotor 27 formed of a conductive material that is substantially inert to the metal produced, such as graphite,

serves as the secondary of a transformer of which thecoil i5 is the primary. Graphite is selected as the material for the rotor 27 inasmuch as it possesses the qualities of good electrical and thermal conductivity as well as ability to withstand temperatures as high as 1500 C. which is necessary in order to maintain the rotor well above the melting point of uranium.

The rotor 27 is provided with upper and lower hubs 29 and 30, respectively, which are integral therewith. A vertically disposed spindle 33, also of graphite, passes through a central vertical opening in the rotor 27, and a collar 34, integral with the spindle 33, supports the rotor 27 approximately midway of the length of the coil i5. A pair of graphite pins 36 and 37 pass through the spindle 33 and the upper and lower hubs 29 and 30, re-` spectively, of the rotor 27 to cause the rotor 27to rotate with the spindle 33. Y

The lower end of the spindle 33 extends downwardly through an opening in the slab l0 and is supported in a water cooled bearing generally indicated at 40. The bearing 40 comprises a cup-shaped member 42 having a centrally located upstanding cylindrical portion 43 which in conjunction with a cover plate 45 and the remainder of the memberv 42 forms an annular chamber 46 for the cooling water, A water inlet connection 48 and a water outlet connection 49 are provided. A plurality of ears 50 are welded to the member 42. Bolts 5l passing through the slab 16 engage the ears 50 to support the bearing 40.

The lower extremity of the spindle 33 isrcarried in a cup 53 the exterior cylindrical surface of which serves as a bearing journal to cooperate with the bearing box formed by the interior cylindrical surface Vof the portion 43 of the member 42. An anti-friction thrust bearing 55 supports the weight of the spindle 33 and the rotor 27. The lower extremity of the spindle 33 is hemispherical in order that heat conduction between the spindle 33 and the cup 53 may be reduced to a minimum. A suitable lubricant is placed in the operating parts of the bearing.

The upper end of the spindle 33 is slotted at 57 to receive a driving pin 59 of a driving member 60 which may be directly connected to an electric motor or may be, for convenience, connected to the spindle of a drill press.

A cover 62 of heat-insulating material rests on the upper edges of the coil-supporting cylinder 11, andrhas a central openingto receive the spindle33. A graphite cylinder 64 surrounds the spindle 33 and extends on either side of the cover 62 to provide protection for the spindle 33 in the area where heated air circulates through the opening in the cover 62 and just past the Spindle. Pins 65 secure the sleeve 64 to the spindle 33.

The charge 69, which may be, for example, composed of uranium tetrailuoride, iodine and calcium in the ratio of 1.33 grams of uranium tetrauoride to 0.33 gram of iodine to 0.5 gram of calcium, is placed in a conical Crucible having its apex remote from the axis of the spindle 33. The Crucible 70 may be of fused beryllia, dolomite or other refractory and preferably is practically non-porous. A ceramic Crucible cover 72 covers the open end of the Crucible 76. Both Crucible 70 and cover 72 are 3. placedV in asteel bomb 73`ar1d`a steel cover 74 is welded or otherwise attached thereto to form a hermetically sealed or at least tightly closedv enclosure for the crucible and its charge. The rotor 27 is provided with recesses toreeeive a plurality of the bombs 73, for example four.

In order to provide for increased heat conduction' from the graphite rotor 27 and the bomb 73, 'moist beryllia 76 ispacked around the bomb 73. The above-described construction is `illustrated both in Figures 1 and 2.

In operation to produce metal on a small scale, it is desirable to preheat both the rotor 27 and the bomb '73 to a temperature as high as is consistent with handling. Sufli'cient heat must be added and/or developed within the reaction mixture to melt the reaction mass and to form the reactants in molten state and to maintain them in molten state'until separation of the metal from the slaghas taken place. The bomb containing the charge isplaced, as shown', in the rotor, high-frequency current is applied to the coil 15, and the spindle 33 and rotor 27 are'rotated at a speed suicient to cause the molten metal produced to move outwardly under the influence of centrifugal force to' form a molten body which will solidify to form a substantially non-porous dense casting or billet 80 as shown in Figure. 1. When enough time has elapsed for the reaction to b'e complete, and the molten metal to collect, the high frequency current may be cut off and the rotation of the rotor 27 continued until the urani um billet 80 has solidified, at which time the bomb 73 may be removed.

vWherev very small charges' are reacted, the nature of the crucible' may have a; substantial effect upon the restilts obtained. For example, where one to two gramcharges are used, much lower yields of metal are secured when the crucibles 70 are porous than when the crucibles are relatively non-porous. Fused dolomite, calcium 0X# ide or beryllium oxide crucibles are suitable.

The process herein described is capable of use generally'in connection with reactions in which a liquid reaction mass is formed and one of the reaction products is im miscible withand has a different density than another of the reaction products or the reaction mass, As previously stated, it is adapted for production of uraniurn byj reaction of a halide of uranium such as UF4, UC14, UI4, or UBr4 withan alkali or alkaline earth metal such as sodium, lithium, magnesium, barium, or calcium.

IMoreover, the inventionmay be applied to reduction of other metal halides sucllas lead chloride, zinc chloride, manganese 'dichlorid'e `or` trichloride, thorium tetrachlorr ide, eerie orceous''chloride or other rare'ear'th chlorides, brylliunrchloride, ort1iecorresponding uorides, bro-y nides or ioddes withthealkali metals or alkaline earth metals. Moreover mixtures of theseV metals such as' thorium and beryllium or uranium and manganese or thoriurnand zinc may be prepared from the mixtures of the corresponding halides. Boosters such as iodine may be used -toY aid in generating Vthe heat' required and to lower the melting point' of the slagto form a molten'rnass;

Moreover, the oxides of some of the above metals may" be reduced with alkali or alkaline earth `metals`to Athe' metallic state, and the molten metal, separated inthe same manner. While the process is especially adapted tothe production of small 'quantities of metal itis adapted'for iuse in production of metal in any convenient quantity. Where large charges are subjected to treatment, it may be convenient to conduct the `reaction in a vertical cylindrical crucible which is rotated about its vertical axis in order to develop the centrifugal force desired.

The following example is illustrative:

Two small cone-shaped crucibles of well vitrifed BeO were loaded with a charge of 0.066 gram of UF4, 0.025 gram of calcium and 0.0165 gram of iodine. The crucibles were placed in small steel bombs, the lids of the bombs'were sealed by welding, and the bombs were mounted in a graphiterotor asl shown in the drawing. The bombs were heated to 1250 C. While being rotated at 2500 R. P. M; After a few minutes the bombs were cooled and opened. A well Vagglomerated button of uranium metal was formed in the top of each crucible.

Although the present invention has been described with reference to the specific details of certain embodiments thereof, it is not intended that such details shall be regarded-aslimitations uponfthe scope of the invention except insofar as included in the accompanying claims.

I claim: l

1. A centrifugal casting device comprising an induction coil disposed about a vertical axis, a vertically disposed graphite spindle carrying a graphite rotor Within said induction coil, at least one recess in said rotor spaced from the bottom thereof and extending to the uppermost level of the rotor, a crucible of conical form disposed in therecess in -said rotor with the apex of said crucible remote from the axis of said spindle, a metal bomb around said crucible' and spaced from said rotor to leave an interspace, a packing of refractory material around said bomb in the interspace whereby the heat conduction into said crucible is improved, and means outside of said coil for'rotating said spindle( 2. A centrifugal casting-device comprising an indue` tion coil disposed about a vertical axis, a vertically disposed graphite spindle carrying a graphite rotor within said induction coil, at least one recess in said rotor; a crucible of conical form disposed in the recess in said rotor with the apex of said crucible remote from the axis of said spindle, a hermetically sealed steel container around said crucible, said container being arranged in the upper part of vsaid rotor; and means outside of said coil for rotating vsaid spindle.

3. The device according to claim 1 in which the packingV consists substantially of wet beryllia.

References Cited in the tile of this patentl UNITED-STATES PATENTS 1,212,426 Voigtlander et al. I an. 16, 1917 1,240,460 Knapp Sept. 18, 1917 1,378,189 Northrup May 17, 1921 2,027,963 De Bats Jan. 14,V 1936 2,085,450 Rohnl June 29, 1937 2,161,950 Christensen June 13, 1939 2,216,567 E'snault-Pelterie Oct. 1, 1940 2,242,759 Schlecht et al May 20, 1941 2,378,042 Sorensen et al. June 12, 1945 FOREIGN PATENTS 361,322 Great Britain Nov. 16, 1931 

